First day I used my Pixel 2 XL I saw ads in the Gmail app. I mean, this is not some $100 phone. I paid 1k for it and Google still showed me ads in Gmail.
The ads are there because you're using gmail the service, not because you're using gmail the app. If you use "gmail the app" with your own imap server or a paid google apps account, you will not see ads.
On the other hand, if there was special code running in the Gmail app to detect if you're on a google phone and behave differently, would you also be annoyed?
